Hi all, I'm Rashiga from Sri Lanka. We also have quite lot of dense leaf users although our country is small. We mostly use imported leaf's Japan (some are also from UK).

Since our country is near the equator we experience out hot climate all through out the year(86 F - 95 F). When I was reading research papers and articles in forums like my nissan leaf I found out that how critical is to have a some sort of active cooling mechanism for the nissan leaf. Best part is our authorized dealer does not handle issues with Nissan leaf. So our option is to save the first battery we got as much as possible before battery prices come down and battery replacement becomes readily available.

These are some methods that came to my mind,1. Using pipes to run coolant below the battery casing and remove the heat using another radiator.2. Using pipes to run coolant below the battery casing and remove the heat using peltier device. 3. Using fans to add an airflow around the battery case

I have some basic issues for using any of the cooling methods, looking at the battery arrangement only some of the modules contact to the battery casing. So will the cooling the battery casing be useful?

Other option is to drill two holes in the battery casing and flood the battery with non conductive fluid and run it through a external radiator. Will it have any harm to the battery, like chemical reactions and even shortage by reaching breakdown voltage of the cooling fluid? Also does the battery casing have enough thickness to be able to tap a thread so pipe fitting can be installed without opening the battery casing?

I want to is it ok to use the vehicle with the under body plastic battery cover removed? Hope this will atleast help to improve the heat transfer to the ambient.

Hope to hear your opinion regrading this!

Thanks in advance.

Last edited by Rashi on Fri Mar 18, 2016 10:01 am, edited 1 time in total.

Shade is your friend. Tree, building, just anything that keeps off the direct sun. Park your car in an area that is cool. Park on a hot road? that heat will radiate to the batteries too.

Charging the car when it is cooler is good too. Charging creates heat. Mid day charging is best to be avoided.

Drive gently, don't "gun it" (as fun as it is to do in this car) pulling out energy from the battery creates heat too as does putting it back in.

Park your car over a puddle of water, in the shade, with a light breeze, so it gets some evaporative cooling from it. not WHEEL deep in the puddle though, it might cause you other issues if it touches the underside (though the battery is supposed to be air tight).

Heat inside the car adds the the overall heat collection, try to keep windows open just a crack. Install window tints if you can or at least those shiny windsheild blockers to keep out the suns heat.

These are just some ideas I've thought of. mostly passive cooling ideas.

Your ideas are beyond my understanding to apply. Once you figure it out, take pictures and maybe even a video. get 'Leaf Spy pro' for android or apple smart phone to connect to the car and view battery temps so you can see if your efforts are working.

Statler: Wake up you old fool. You slept through the show.Waldorf: Who's a fool? You watched it.

The car is designed for passive cooling of the pack with air, while moving. You should be able to use a fan or two to blow air into the cooling air intakes. A jug of ice behind each fan would lower the incoming air's temp a bit.

Filling the case with fluid is an interesting concept. The first (really big) question is whether there's a fluid that could safely be introduced into the pack long-term. Second question is how much such a fluid would cost, and then there is weight. Finally, how fluid-tight is the case once it's filled with many pounds of liquid and subjected to G-forces.

Assuming all these work out, it probably help to conduct heat from the cell internals to the metal case (much better than air), where you could then extract it fairly easily in a number of ways.

Nubo wrote:Filling the case with fluid is an interesting concept. The first (really big) question is whether there's a fluid that could safely be introduced into the pack long-term. Second question is how much such a fluid would cost, and then there is weight. Finally, how fluid-tight is the case once it's filled with many pounds of liquid and subjected to G-forces.

Assuming all these work out, it probably help to conduct heat from the cell internals to the metal case (much better than air), where you could then extract it fairly easily in a number of ways.

Take from those using liquid cooling for computer boards, it sounds cool but is not practical. First you need a liquid that is an electrical insulator (for obvious reasons electric car), and then you want something that won't corrode or mess up any internal wiring, battery, etc. The problem is, just about anything liquid is going to have some weird reaction with metal. Air just works better as being the least reactive. Add in what has mentioned, extra weight, sloshing, leaking, etc. It would be better to just vent filtered air through the battery pack given all it would take create the desired effect using liquid.

I also have been considering some solutions but haven't yet put myself to full task of developing such a system. In our hot climate of Arizona USA, pushing hot air around a hot battery is meaningless. Also as previously mentioned, the car interior heats up when parked as well as parking over a hot surface.

A blowing fan may be slightly helpful in the interior of the car while parked and on the outside of the battery case but mostly not.

I have also considered a heat reflective addition or sticky to the plastic shield between the ground and the battery.

A belly shell to the battery outside case that could hold a cooling liquid. or A/C coolant lines and blower.

Plumbing existing A/C cooling in the cabin up the console channel between the seats to the hole in the floor forward/ahead of the back seats while either just blowing on the outer case or (better) going in through the the top of the case (watertight) and exhausting as high as possible in the engine compartment or body exterior at the rear as high as possible using anti backflow.

Also considered the direct liquid cooling of the pack with circulating pump and radiator using an appropriate oil that would not be corrosive or damaging to electronics or metals and other components.

The bad thing about using ambient air or liquids in a hot climate is they are also hot or become hot and less effective unless cooled by more than just airflow. I think the best way is going to involve refrigerant.

Here's kind of a gold-plated suggestion (in the sense of cost, not necessarily value): use a translacent heat pipe to move the battery's heat out to some external radiator. It would be way easier to keep the battery pack sealed that way, and I understand there are some clever ways to control the "thermal conductivity" of such an arrangement, which would let one switch the pack from an insulated condition for wintertime use, to a heatsunk condition for summer.

You folks did read my portable A/C unit suggestion, right? It cools and dehumidifies the air, has a heat exhaust hose as well as a cool air hose, and costs about $400. You can even select levels of cooling. Instead of plumbing a car that wasn't meant for liquid cooling, you instead simulate a cost down a long hill on a chilly night, or at least a cool one. All you need is the A/C unit and an adapter duct that you make for the car.

LeftieBiker wrote:You folks did read my portable A/C unit suggestion, right? It cools and dehumidifies the air, has a heat exhaust hose as well as a cool air hose, and costs about $400. You can even select levels of cooling. Instead of plumbing a car that wasn't meant for liquid cooling, you instead simulate a cost down a long hill on a chilly night, or at least a cool one. All you need is the A/C unit and an adapter duct that you make for the car.

That may be feasible here in North America, but in Sri Lanka an A/C unit might be a rather expensive luxury.